The Dirty Secret

The Dirty Secret

Coal supplies 24 percent of all global energy and 40 percent of all electricity, and it spews more carbon than any other fossil source – kilowatt for kilowatt, twice as much as natural gas. Yet coal is the most abundant fossil fuel, and its use is intensifying. While estimates of remaining fossil supplies vary, the World Coal Institute says there are 164 years’ worth of coal still in the ground, in contrast to just 41 years’ worth of oil. Coal is being enthusiastically mined not only in the United States but also in India and China (where at least 79 percent of electricity comes from coal). The equivalent of more than 1,400 500-megawatt coal power plants are planned worldwide by 2020, according to the Natural Resources Defense Council. This includes 140 U.S. plants of various sizes. “Coal is going to be used. It was a bad joke played by God that oil and gas were put where there is no demand, and coal was put in China, India, and the United States,” says Ernest J. Moniz, an MIT physicist and a former under-secretary of the U.S. Department of Energy.

In short, we’re stuck with coal. Since there’s little reason to expect that humankind will stop digging for it, we will have to find cleaner ways to burn it. This was made clear by a Princeton University analysis that showed immediate ways to reduce carbon dioxide emissions. The analysis goes like this: Already, humankind is pumping about seven billion tons of carbon per year into the atmosphere, about three times as much as in the 1950s, and that figure looks likely to double by 2055. (These tonnages are for carbon; for carbon dioxide, multiply by 3.7.) At that rate, we’re on track to triple atmospheric carbon dioxide concentrations from preindustrial levels, creating temperatures not seen since three million years ago, when sea levels were 15 to 35 meters higher (see “The Messenger”).

But the Princeton group, called the Carbon Mitigation Initiative, showed that it’s possible, with today’s technologies, to deploy a variety of strategies that would each save one billion tons of carbon emissions per year. Deploy seven over the next 50 years and you’ve at least stopped the increase in carbon emissions. The group calls each billionton saving a “wedge.” Its report showed that sequestering carbon from 800 coal power plants – or 180 coal-based synfuels plants, which make liquid fuels – would furnish a wedge each. So would tripling nuclear power, doubling automotive efficiency, and implementing the best available energy efficiency technologies in buildings (see “The Un-Coal”). “These aren’t pipe dreams. These are here today and could be deployed at scale,” says Princeton’s Robert Socolow, a professor of mechanical engineering and codirector of the Carbon Mitigation Initiative.

But not all wedges are created equal. If we “get the automobiles wrong,” says Socolow, it’s not an insurmountable problem, because “they are not going to be there 20 years from now. But when we build a power plant – a new one – it’s going to be around for 50 or 60 years.” And that – along with coal’s impending status as the remaining cheap fossil fuel – is why a discussion of wedges very soon becomes a discussion of coal.